A basic checklist for troubleshooting VLAN interfaces and bridging on MX Series devices.To troubleshoot Physical interface or IRB interfaces, refer to KB26486: Troubleshooting Checklist - Ethernet Physical Interface [juniper.net] or KB26488: Troubleshooting Checklist - IRB Interface [juniper.net] .
Use the following checklist to troubleshoot VLAN interfaces and bridging:
Verify the configuration of the VLAN.
For details on VLANs and bridging and its configuration on a MX router, refer to the technical documentation:
Below are some common configuration mistakes to check for:
Make sure the physical and logical interfaces are in the UP UP condition, AND that the family is set as ‘bridge’ on the logical interface (for all the interested interfaces).
show interfaces terse ge-x/x/x
show interfaces terse ge-x/x/x .yyy
Physical Interface output:
user@router> show interfaces terse | match ge-1/0/0 Interface Admin Link Proto Local Remote ge-1/0/0 up up
If physical interface is down, then refer to physical interface checklist, KB26486 - Troubleshooting Checklist - Ethernet Physical Interface [juniper.net] .
Logical Interface output:
user@router> show interfaces terse ge-8/0/0.3122 Interface Admin Link Proto Local Remote ge-8/0/0.3122 up up bridge
If logical interface is admin down, then verify the configuration and see if it is disabled. If its link status is down, verify that the physical interface is UP.
Verify the logical interfaces associations with the VLAN & bridge-domains.
show bridge domain
show bridge domain <vlan> detail
For example:
user@router> show bridge domain Routing instance Bridge domain VLAN ID Interfaces default-switch vlan_100 100 ge-1/0/0.0 ge-1/0/1.0 ge-1/0/3.0 default-switch vlan_200 200 ge-1/0/2.0 ge-1/0/3.0 ge-1/1/4.0 user@router> show bridge domain vlan_100 detail Routing instance: default-switch Bridge domain: vlan_100 State: Active Bridge VLAN ID: 100 Interfaces: ge-1/0/0.0 ge-1/0/1.0 ge-1/0/3.0 Total mac count: 2
In the above output, the vlan_100 bridge domain has three interfaces associated with it, which are all part of VLAN 100.
View the MAC Address Table.
After verifying the correct interface associations for the VLAN/BRIDGE_DOMAIN (in Step 3), use the ' show bridge mac-table' command to view the MAC entries for the logical interfaces (for the interested bridge domain).
show bridge mac-table'
user@router> show bridge mac-table MAC flags (S -static MAC, D -dynamic MAC, SE -Statistics enabled, NM -Non configured MAC) Routing instance : default-switch Bridging domain : vlan_100, VLAN : 100 MAC MAC Logical address flags interface 00:21:59:ab:8a:95 D ge-1/0/0.0 00:21:59:ab:8a:96 D ge-1/0/1.0
The show bridge mac-table command is used view all the entries within the MAC address table. It generates a list of learned MAC addresses along with the corresponding VLANs and interfaces. All entries are organized based on their associated VLANs. For more information on the above command output, refer to http://www.juniper.net/techpubs/en_US/junos/topics/reference/command-summary/show-bridge-mac-table-command.html .
show bridge mac-table
If for any reason the table entries in the above output are not valid or you want to flush the MAC entries during troubleshooting, use the command ‘ clear bridge mac-table ’:
clear bridge mac-table
user@router> clear bridge mac-table ? Possible completions: <[Enter]> Execute this command
The clear bridge mac-table command clears all entries in the table or entries based on a specific property. Optionally, you can use the interface option to clear only those MAC table entries learned through the specified interface. For more information on the above command output, refer to http://www.juniper.net/techpubs/en_US/junos/topics/reference/command-summary/clear-bridge-mac-table-command.html
Monitor Bridge Statistics.
Now after verifying configuration’s and correct interface and MAC associations, check if the intended traffic types are hitting the bridge by using the command ‘ show bridge statistics ’:
show bridge statistics
user@router> show bridge statistics Local interface: ge-1/0/0.111, Index: 81 Broadcast packets: 31 Broadcast bytes : 1984 Multicast packets: 0 Multicast bytes : 0 Flooded packets : 31 Flooded bytes : 2362 Unicast packets : 24093 Unicast bytes : 2553438 Current MAC count: 1 (Limit 1024) Local interface: ge-1/0/0.112, Index: 80 Broadcast packets: 0 Broadcast bytes : 0 Multicast packets: 0 Multicast bytes : 0 Flooded packets : 0 Flooded bytes : 0 Unicast packets : 0 Unicast bytes : 0 Current MAC count: 0 (Limit 1024
The above output shows statistics for BUM traffic as well as for flooding for each logical interface of each bridge domain and for each routing instance. For more information on the above command output, refer to http://www.juniper.net/techpubs/en_US/junos/topics/reference/command-summary/show-bridge-statistics-command.html .